Meeting Abstract

P2.79  Wednesday, Jan. 5  Body composition and developmental maturity in chronically restricted nestling House sparrows. KILLPACK, TL*; STONE, K; KARASOV, WH; Univ. of Wisconsin, Madison; MMSD High School Science Research Internship Program ; Univ. of Wisconsin, Madison tkillpack@wisc.edu

Food restriction has been shown to alter body composition and development in altricial birds, and some body components (e.g. assimilation organs such as intestine and liver) may be more responsive to food limitation than others (e.g. skeletal and nervous system). We hypothesized that chronically food-restricted nestling birds maintain skeletal growth, yet growth and developmental maturity of muscles and organs of assimilation would be reduced. House sparrow (Passer domesticus) nestlings were raised in the laboratory from day 3 to 12 post-hatch and fed age-specific meal sizes (controls) or meals 75% of age-specific size (restricted group). Skeletal measurements were taken, and flight and leg muscles and organs were dissected and analyzed for composition at day 6, 9, and 12 post-hatch. Skull, wing, and tarsus lengths were not significantly different between control and food restricted birds. Food restricted birds at day 9 and day 12 had significantly smaller body mass and muscle masses compared to same-aged controls. Proportion of water in the muscles, considered an index for developmental immaturity, was significantly higher in food-restricted birds at days 9 and 12. Food-restricted birds at day 12 also had significantly lower hematocrit values. Intestine and liver masses were significantly lower in food-restricted birds and digestive enzymatic capacity was reduced as a result of decreased intestine mass. From these data, it appears that altricial birds chronically restricted throughout the nestling period maintain structural growth at the expense of muscle and organ development. Support: NSF IOS0615678 to WHK, NSF GRFP to TLK.